The present invention relates to a data converting apparatus, a method thereof, and a record medium, in particular, those that allow a picture whose quality is almost the same as an original picture to be restored.
The inventor of the present invention has proposed a technology for generating a high resolution picture with a low resolution picture. The proposed technology is disclosed as Japanese Patent Laid-Open Publication No. HEI 10-93980. In the technology, with a low resolution picture of which a high resolution original is reduced, a high resolution picture whose quality is almost the same as the original picture is restored. In this proposed technology, for example, as shown in FIG. 1, pixel values of (3xc3x973) pixels a to i around a pixel i of a high resolution picture (a restored picture) corresponding to a considered pixel I of a low resolution picture (a higher hierarchical level picture) are obtained by calculating for example a linear combination of a plurality of pixels (for example, (3xc3x973) pixels A to I) of a low resolution picture adjacent to the pixels a to i and predetermined predictive coefficients. In addition, an error between the pixel values of the restored picture and the pixel values of the original picture is calculated. Corresponding to the calculated result, the pixel values of the low resolution picture or the predictive coefficients are (is) repeatedly updated.
However, as was described above, in such a method, although the error between the pixel values of the restored picture and the pixel values of the original picture is gradually becoming small, the decreasing speed of the error is low. To cause the error to be lower than a desired threshold value, the pixel values of the low resolution picture or the predictive coefficients should be repeatedly updated.
Therefore, an object of the present invention is to allow a compressed picture to be restored to an original picture by updating pixel values of a low resolution picture and predictive coefficients and performing a non-linear process for the updated results.
The invention of claim 1 is a picture data converting apparatus for converting first picture data into second picture data whose quality is lower than the first picture data, comprising:
an intermediate picture data generating portion for generating intermediate picture data whose quality is almost the same as the second picture data with the first picture data;
a storing portion for storing the intermediate picture data;
a predictive picture data generating portion for generating predictive picture data whose quality is almost the same as the first picture data according to the intermediate picture data stored in the storing portion and predictive coefficients;
an error detecting portion for detecting an error between the first picture data and the predictive picture data;
a first determining portion for determining whether or not a variation amount of the error detected by the error detecting portion is equal to or larger than a first threshold value;
a second determining portion for determining whether or not the error detected by the error detecting portion is equal to or larger than a second threshold value; and
an adjusting portion for performing a first adjusting process for pixel value of the intermediate picture data stored in the storing portion based on the first input picture data when the variation amount of the error is equal to or larger than the first threshold value as the determined result of the first determining portion,
for performing a second adjusting process for a pixel value of the intermediate picture data stored in the storing portion with a non-linear variation amount when the variation amount of the error is smaller than the first threshold value as the determined result of the first determining portion and when the error is equal to or larger than the second threshold value as the determined result of the second determining portion, and
for determining the intermediate picture data stored in the storing portion as the second picture data when the error is smaller than the second threshold value as the determined result of the second determining portion.
The invention of claim 8 is a picture data converting method for converting first picture data into second picture data whose quality is lower than the first picture data, comprising the steps of:
generating intermediate picture data whose quality is almost the same as the second picture data with the first picture data;
storing the intermediate picture data;
generating predictive picture data whose quality is almost the same as the first picture data according to the stored intermediate picture data and predictive coefficients;
detecting an error between the first picture data and the predictive picture data;
determining whether or not a variation amount of the detected error is equal to or larger than a first threshold value;
determining whether or not the detected error is equal to or larger than a second threshold value;
performing a first adjusting process for a pixel value of the stored intermediate picture data based on the first input picture data when the variation amount of the error is equal to or larger than the first threshold value;
performing a second adjusting process for a pixel value of the stored intermediate picture data with a non-linear variation amount when the variation amount of the error is smaller than the first threshold value and when the error is equal to or larger than the second threshold value; and
determining the stored intermediate picture data as the second picture data when the error is smaller than the second threshold value.
The invention of claim 15 is a data converting apparatus for converting first data into second data whose quality is lower than the first data, comprising:
an intermediate data generating portion for generating intermediate data whose quality is almost the same as the second data with the first data;
a storing portion for storing the intermediate data;
a predictive data generating portion for generating predictive data whose quality is almost the same as the first data according to the intermediate data stored in the storing portion and predictive coefficients;
an error detecting portion for detecting an error between the first data and the predictive data;
a first determining portion for determining whether or not a variation amount of the error detected by the error detecting portion is equal to or larger than a first threshold value;
a second determining portion for determining whether or not the error detected by the error detecting portion is equal to or larger than a second threshold value; and
an adjusting portion for performing a first adjusting process for data values of the intermediate data stored in the storing portion based on the first input data when the variation amount of the error is equal to or larger than the first threshold value as the determined result of the first determining portion,
for performing a second adjusting process for data values of the intermediate data stored in the storing portion with a non-linear variation amount when the variation amount of the error is smaller than the first threshold value as the determined result of the first determining portion and when the error is equal to or larger than the second threshold value as the determined result of the second determining portion, and
for determining the intermediate data stored in the storing portion as the second data when the error is smaller than the second threshold value as the determined result of the second determining portion.
The invention of claim 22 is a data converting method for converting first data into second data whose quality is lower than the first data, comprising the steps of:
generating intermediate data whose quality is almost the same as the second data with the first data;
storing the intermediate data;
generating predictive data whose quality is almost the same as the first data according to the stored intermediate data and predictive coefficients;
detecting an error between the first data and the predictive data;
determining whether or not a variation amount of the detected error is equal to or larger than a first threshold value;
determining whether or not the detected error is equal to or larger than a second threshold value;
performing a first adjusting process for a data value of the stored intermediate data based on the first input data when the variation amount of the error is equal to or larger than the first threshold value,
performing a second adjusting process for a data value of the stored intermediate data with a non-linear variation amount when the variation amount of the error is smaller than the first threshold value and when the error is equal to or larger than the second threshold value, and
determining the stored intermediate data as the second data when the error is smaller than the second threshold value.
The invention of claim 29 is a record medium on which a program that causes a computer to convert first picture data into second picture data whose quality is lower than the first picture data is recorded, the program comprising the steps of:
generating intermediate picture data whose quality is almost the same as the second picture data with the first picture data;
storing the intermediate picture data;
generating predictive picture data whose quality is almost the same as the first picture data according to the stored intermediate picture data and predictive coefficients;
detecting an error between the first picture data and the predictive picture data;
determining whether or not a variation amount of the detected error is equal to or larger than a first threshold value;
determining whether or not the detected error is equal to or larger than a second threshold value;
performing a first adjusting process for a pixel value of the stored intermediate picture data based on the first input picture data when the variation amount of the error is equal to or larger than the first threshold value;
performing a second adjusting process for a pixel value of the stored intermediate picture data with a non-linear variation amount when the variation amount of the error is smaller than the first threshold value and when the error is equal to or larger than the second threshold value; and
determining the stored intermediate picture data as the second picture data when the error is smaller than the second threshold value.
The invention of claim 30 is a record medium on which a program that causes a computer to convert first data into second data whose quality is lower than the first data is recorded, the program comprising the steps of:
generating intermediate data whose quality is almost the same as the second data with the first data;
storing the intermediate data;
generating predictive data whose quality is almost the same as the first data according to the stored intermediate data and predictive coefficients;
detecting an error between the first data and the predictive data;
determining whether or not a variation amount of the detected error is equal to or larger than a first threshold value;
determining whether or not the detected error is equal to or larger than a second threshold value;
performing a first adjusting process for data values of the stored intermediate data based on the first input data when the variation amount of the error is equal to or larger than the first threshold value,
performing a second adjusting process for a data value of the stored intermediate data with a non-linear variation amount when the variation amount of the error is smaller than the first threshold value and when the error is equal to or larger than the second threshold value, and
determining that the stored intermediate data is the second data when the error is smaller than the second threshold value.
The invention of claim 31 is a picture data converting apparatus for converting first picture data into second picture data whose quality is lower than the first picture data, comprising:
an intermediate picture data generating portion for generating intermediate picture data whose quality is almost the same as the second picture data with the first picture data;
a storing portion for storing the intermediate picture data;
a predictive picture data generating portion for generating predictive picture data whose quality is almost the same as the first picture data according to the intermediate picture data stored in the storing portion and predictive coefficients;
an error detecting portion for detecting an error between the first picture data and the predictive picture data;
a first determining portion for determining whether or not the error detected by the error detecting portion is equal to or larger than a first threshold value and determining the intermediate picture data as the second picture data when the error is smaller than the first threshold value;
a second determining portion for determining whether or not the number of times a linear adjusting process is successively performed is equal to or larger than the second threshold value when the error is equal to or larger than the first threshold value as the determined result of the first determining portion;
a first adjusting portion for linearly adjusting a pixel value of the intermediate picture data when the number of times is smaller than the second threshold value as the determined result of the second determining portion; and
a second adjusting portion for non-linearly adjusting a pixel value of the intermediate picture data when the number of times is equal to or larger than the second threshold value as the determined result of the second determining portion,
wherein the predictive picture data generating portion generates the predictive coefficients whenever the first adjusting portion and the second adjusting portion adjust the pixel value.
The invention of claim 36 is a picture data converting method for converting first picture data into second picture data whose quality is lower than the first picture data, comprising the steps of:
generating intermediate picture data whose quality is almost the same as the second picture data with the first picture data;
storing the intermediate picture data;
generating predictive picture data whose quality is almost the same as the first picture data according to the stored intermediate picture data and predictive coefficients;
detecting an error between the first picture data and the predictive picture data;
determining whether or not the detected error is equal to or larger than a first threshold value and determining the intermediate picture data as the second picture data when the error is smaller than the first threshold value;
determining whether or not the number of times a linear adjusting process is successively performed is equal to or larger than the second threshold value when the error is equal to or larger than the first threshold value;
linearly adjusting pixel value of the intermediate picture data when the number of times is smaller than the second threshold value; and
non-linearly adjusting pixel value of the intermediate picture data when the number of times is equal to or larger than the second threshold value,
wherein the predictive coefficients are generated whenever the linear adjustment and the non-linear adjustment are performed.
The invention of claim 41 is a data converting apparatus for converting first data into second data whose quality is lower than the first data, comprising:
an intermediate data generating portion for generating intermediate data whose quality is almost the same as the second data with the first data;
a storing portion for storing the intermediate data;
a predictive data generating portion for generating predictive data whose quality is almost the same as the first data according to the intermediate data stored in the storing portion and predictive coefficients;
an error detecting portion for detecting an error between the first data and the predictive data;
a first determining portion for determining whether or not the error detected by the error detecting portion is equal to or larger than a first threshold value and determining the intermediate data as the second data when the error is smaller than the first threshold value;
a second determining portion for determining whether or not the number of times a linear adjusting process is successively performed is equal to or larger than the second threshold value when the error is equal to or larger than the first threshold value as the determined result of the first determining portion;
a first adjusting portion for linearly adjusting data value of the intermediate data when the number of times is smaller than the second threshold value as the determined result of the second determining portion; and
a second adjusting portion for non-linearly adjusting data value of the intermediate data when the number of times is equal to or larger than the second threshold value as the determined result of the second determining portion,
wherein the predictive data generating portion generates the predictive coefficients whenever adjustments at the first adjusting portion and the second adjusting portion are performed.
The invention of claim 48 is a data converting method for converting first data into second data whose quality is lower than the first data, comprising the steps of:
generating intermediate data whose quality is almost the same as the second data with the first data;
storing the intermediate data;
generating predictive data whose quality is almost the same as the first data corresponding to the stored intermediate data and predictive coefficients;
detecting an error between the first data and the predictive data;
determining whether or not the detected error is equal to or larger than a first threshold value and determining the intermediate data as the second data when the error is smaller than the first threshold value;
determining whether or not the number of times a linear adjusting process is successively performed is equal to or larger than the second threshold value when the error is equal to or larger than the first threshold value;
linearly adjusting data value of the intermediate data when the number of times is smaller than the second threshold value; and
non-linearly adjusting data value of the intermediate data when the number of times is equal to or larger than the second threshold value,
wherein the predictive coefficients are generated whenever the linear adjustment and the non-linear adjustment are performed.
The invention of claim 54 is a record medium on which a program that causes a computer to convert first picture data into second picture data whose quality is lower than the first picture data is recorded, the program comprising the steps of:
generating intermediate picture data whose quality is almost the same as the second picture data with the first picture data;
storing the intermediate picture data;
generating predictive picture data whose quality is almost the same as the first picture data according to the stored intermediate picture data and predictive coefficients;
detecting an error between the first picture data and the predictive picture data;
determining whether or not the detected error is equal to or larger than a first threshold value and determining the intermediate picture data as the second picture data when the error is smaller than the first threshold value;
determining whether or not the number of times a linear adjusting process is successively performed is equal to or larger than the second threshold value when the error is equal to or larger than the first threshold value;
linearly adjusting pixel value of the intermediate picture data when the number of times is smaller than the second threshold value; and
non-linearly adjusting pixel value of the intermediate picture data when the number of times is equal to or larger than the second threshold value,
wherein the predictive coefficients are generated whenever the linear adjustment and the non-linear adjustment are performed.
The invention of claim 55 is a record medium on which a program that causes a computer to convert first data into second data whose quality is lower than the first data is recorded, the program comprising the steps of:
generating intermediate data whose quality is almost the same as the second data with the first data;
storing the intermediate data;
generating predictive data whose quality is almost the same as the first data according to the stored intermediate data and predictive coefficients;
detecting an error between the first data and the predictive data;
determining whether or not the detected error is equal to or larger than a first threshold value and determining the intermediate data as the second data when the error is smaller than the first threshold value;
determining whether or not the number of times a linear adjusting process is successively performed is equal to or larger than the second threshold value when the error is equal to or larger than the first threshold value;
linearly adjusting picture value of the intermediate data when the number of times is smaller than the second threshold value; and
non-linearly adjusting picture value of the intermediate data when the number of times is equal to or larger than the second threshold value,
wherein the predictive coefficients are generated whenever the linear adjustment and the non-linear adjustment are performed.